During spermatogenesis in a variety of mammals unusual basic chromosomal proteins appear in germ cells as they progress through specific stages of development. This proposal concentrates on two such entities, a prominent testicular lysine rich histone component (H1-X) that is associated with meiosis, and a testis-specific basic protein (TSBP) associated with spermatid development. Experiments using the rat as model animal are designed to gain insight into the functional roles of these two proteins. Antisera raised against TSBP will be used for its immuno-histological identification in specific spermatid nuclei. The "half life" of TSBP will be examined, and its mode of association with DNA will be probed by proteolytic and nucleolytic techniques. Comprehension of the requirement for a massive change in distribution of H1 species with respect to peptide fingerprints, distribution of phosphorylation sites, and ability to serve as substrate for partially purified testicular protein kinases. Effects of both androgen and FSH on the synthesis of each of these proteins will be examined in hypophysectomized mature rats as well as in immature animals receiving treatment with high doses of testosterone. Principal methods include ion-exchange column chromatography, polyacrylamide gel electrophoresis, and radioisotope techniques.